Field of the Invention
The present disclosure relates to a fuel cell stack.
Discussion of the Background
In general, a solid polymer electrolyte fuel cell includes a solid polymer electrolyte membrane, which is a polymer ion-exchange membrane. The fuel cell includes a membrane electrode assembly (MEA), in which an anode electrode is disposed on one surface of the solid polymer electrolyte membrane and a cathode electrode is disposed on the other surface of the solid polymer electrolyte membrane. The anode electrode and the cathode electrode each include a catalyst layer (electrode catalyst layer) and a gas diffusion layer (porous carbon).
The membrane electrode assembly and a cathode separator and an anode separator that sandwich the membrane electrode assembly constitute a power generation cell (unit fuel cell). An oxidant gas flows over the cathode separator along an electrode surface. A fuel gas flows over the anode separator along the electrode surface. A predetermined number of power generation cells are stacked and used, for example, as a vehicle fuel cell stack.
In the fuel cell stack, the temperatures of some of the power generation cells tend to decrease more easily than those of other power generation cells due to dissipation of heat to the outside. For example, the temperature of a power generation cell that is disposed at an end in the stacking direction (hereinafter, referred to as an “end power generation cell”) decreases particularly easily, because heat of the end power generation cell is dissipated to the outside through an electric power output terminal plate (collector plate), an end plate, and the like.
For example, Japanese Unexamined Patent Application Publication No. 2013-149595 describes a fuel cell stack for solving this problem. The fuel cell stack includes a stacked body in which power generation cells are stacked; and terminal plates, insulation members, and end plates disposed on both sides of the stacked body in the stacking direction. At least one of the insulation members has a recess that has an opening facing the stacked body. A heat-insulating member and a terminal plate are accommodated in the recess.
It is described that, with such a structure, dissipation of heat from the outer peripheries of the heat-insulating member and the terminal plate can be effectively suppressed; a decrease in the temperature of an end power generation cell, which is disposed in an end portion of the stacked body, can be reliably suppressed; and the fuel cell stack can maintain high power generation performance.